<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>表头单元格th</title>
</head>
<body>
    
    <h1>表头单元格th</h1>
    <h2>th标签内容会加粗居中</h2>
    <table>
        <tr>
            <th>姓名</th><th>性别</th><th>年龄</th>
        </tr>
        <tr>
            <td>签内容会加粗</td><td>签内容会加粗</td><td>签内容会加粗</td>
        </tr>
        <tr>
            <td>1</td><td>2</td><td>3</td>
        </tr>
        <tr>
            <td>1</td><td>2</td><td>3</td>
        </tr>
    </table>

</body>
</html>